横流冷却塔改造成逆流冷却塔的实施及效果

介绍了逆流冷却塔的冷却特点和热工性能,并将逆流冷却塔应用到公司对原横流冷却塔的改造中,成功地将单塔冷却水量从2700t/h提升到3000t/h。同时对冷却塔改造的热焓平衡进行了验算。从改造后冷却塔的实际运行情况可知,对冷却塔的改造达到了预期的效果。     

冷却塔水轮机并水改造的技术开发与应用

阐述了冷却塔的水轮机取代电动风机节能改造的原理,研究了冷却塔水轮机并水改造技术,并应用到新钢公司第二炼钢厂净循环水系统冷却塔的节能改造,对节能改造效果作出了评价。     

逆流式冷却塔性能分析及改造研究

根据实测数据及现场观察分析,找出了连铸冷却塔冷却能力不足的原因,在此基础上对淋水填料、布水系统、收水系统等进行了改造,并运用焓差法对冷却塔热力性能、通风阻力性能进行计算,确定了冷却塔核心部件淋水装置的改造参数.根据改造后的冷却塔性能检测的数据.证实冷却塔的热力性能得到了明显的提升.     

循环水冷却塔的改造

分析了循环水冷却塔存在的问题,重点论述了冷却塔的改造及其经济效益。     

横流冷却塔边层填料破损原因及处理措施

对循环水冷却塔边层填料大量快速损坏的原因进行了分析探讨。提出了解决这一问题的几种方法,对这几种方法的优、缺点及可行性进行了对比,确定了切实可行的冷却塔改造方案。采用这一方案对冷却塔进行了改造,收到了较好的效果。为此类冷却塔的改造提供了理论上和实践上的依据。     

自然通风冷却塔的改造

分析了处理循环水量为5000t／h的自然通风冷却塔冷却能力低的原因;采取更新喷嘴、更换填料、改变填料支撑梁的结构、加装挡水闸门和导水板等措施对冷却塔进行了改造。结果表明,改造后进出冷却塔的循环水温差提高了3℃,且机组电耗降低。     

冷却塔与节能

回顾了冷却塔的发展历程,从冷却塔设计时工艺参数的选择、气动特性的优化、老塔的挖潜改造、风机的选型与匹配等方面,阐述了冷却塔的节能方法,认为老塔的挖潜改造和水泵扬程的正确选取是冷却塔节能的重要方面。     

节水消雾技术在某煤化工项目循环水冷却塔系统改造中的应用

对循环水冷却塔进行节水消雾改造。在不增加原塔基础荷载、空冷器换热面积可控、干湿联合的前提下,对现有部分冷却塔进行了改造。改造后的冷却塔技术先进,运行良好,冬季羽雾明显降低,达到了节水消雾的预期效果,具有明显的经济效益和社会效益。     

降雾节水型冷却塔在榆林炼油厂的应用

分析了榆林炼油厂2×3 000 m~3N/h循环水装置运行状况,在此基础上,提出对原循环水冷却塔存在的缺陷进行科学改造,将原来普通的冷却塔改造成降雾节水型冷却塔。1年多生产运行实践结果表明,改造后装置的降雾节水效果明显,企业取得可观的经济和社会效益,可为企业水处理系统节水改造提供借鉴和参考。     

无填料喷雾冷却塔在湿法磷酸装置中的应用

阐述传统填料冷却塔在湿法磷酸装置应用中存在的问题,将冷却塔改造为无填料喷雾冷却塔,介绍改造方案.冷却塔改造后,冷却温差大,风阻小,运行稳定可靠,处理水量大,节能效果显著,无飘水现象,具有良好的经济和环保效益.     

ACR对PVC加工性能的影响

详细研究了丙烯酸酯类PVC加工助剂———ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明,随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高,其塑化速度增大,但熔体强度降低,在组成相同的情况下,特性黏度越大,塑化越慢,熔体强度越大;丙烯酸酯类加工助剂对PVC制品的拉伸强度和维卡软化点无明显影响,高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

Molecular mechanics modelling of interfacial energy and flexibility on cellulose

Molecular mechanics modelling is used to calculate the energies of interaction, hence the molecular level energy of adhesion at the interface with crystalline cellulose I of three different photopolymerizable primers and of a polyester varnish at the interface with the primer/cellulose assembly. The energy of interactions for just one of the primers with the statistically most common conformation of amorphous cellulose has also been obtained for comparison. Experimental results of adhesion by a standard peel test and by thermomechanical analysis, in which the effect of viscoelastic energy dissipation by crack tip propagation has been respectively minimized or is not present, hence in which the energy of interfacial interaction is nothing else but the work of adhesion, correlated well with the energies of interaction calculated by molecular mechanics. An equation correlating the energy of interaction at each finish/cellulose interface with the deflection derived by thermomechanical analysis, and with the number of internal bond rotational degrees of freedom as well as the degree of networking of the finish, has been derived and is presented. A relationship between the intrinsic fracture energy Go and the molecular mechanics-derived energy of interaction at the interface equating this to the square of the work of adhesion is obtained and is presented.     

Functional properties of proteins in foods

The measurement of functionality of protein food ingredients has developed somewhat haphazardly, probably due to the wide range of proteins used as ingredients and the diversity of foods. Studies of the physiochemical properties of proteins should enable prediction of a proteins response to process environments and prove more fruitful than many of the empirical measurements of functionality. The effects of pH, salt type and concentration on the phase behaviour of the oilseed globulin and arachin, demonstrates the complexity of protein solubility and the inadequacies of simple tests that have arisen. Studies of the effects of salts and conditioning on meat fibres, coupled with measurement of the location of water in pellets from water holding tests enable the latter to be applied with increased confidence. Comparison of the endothermic transitions observed on heating with the development of storage and loss moduli allow the contributions of domains of skeletal muscle myosin to gel structure to be investigated.     

Aggregation pheromone system of adult gregarious desert locust schistocerca gregaria (forskal)

Six electrophysiologically active aromatic compounds, viz., anisole, benzaldehyde, veratrole, guaiacol, phenylacetonitrile, and phenol, were identified in the volatiles of older-adult male desert locust. Young adults and females of all age groups produced none or only trace quantities of these compounds. Comparison of the aggregation responses of young and older adults to the crude, older-adult, volatile extract and different synthetic blends of the six compounds showed that the aggregation pheromone system of the adult gregarious locust consists of phenylacetonitrile, guaiacol, phenol, and benzaldehyde. Like the crude volatile extract of older males, neither the synthetic blend of the six compounds nor the adult pheromone blend evoked any significant aggregation responses from nymphs. These results confirm our previous report of sexual differentiation in the production of adult aggregation pheromone in the desert locust and of the evidence of two distinct aggregation pheromone systems in the two stages of the insect.     

硼酸钙对铜渣中夹杂铜沉降效果的影响

考察了添加剂CaB2O3对转炉铜渣中夹杂铜沉降效果的影响，并结合铜渣的粘度测试及红外光谱表征，研究其影响机理，采用FactSage软件计算了添加剂对铜渣液相线温度的影响。结果表明，随添加剂含量增大，铜渣中夹杂铜的沉降效果逐渐增强，添加剂含量由0增至6wt%时，底部渣含铜量由4.10wt%增至6.85wt%，这是由于添加剂可有效降低铜渣粘度。随添加剂含量增大，渣粘度降低，但降低效果随温度增大而趋于平缓。随添加剂含量增大，铜渣的硅酸盐结构趋于简化，添加剂通过破坏铜渣复杂的硅酸盐结构降低铜渣粘度。铜渣的液相线温度随添加剂含量增大而减小，添加剂通过减少渣中固体颗粒的方式降低铜渣粘度。     

水平及竖直基底上微小固着液滴的蒸发特性分析

为揭示非水平表面上微小蒸发液滴的传热传质特性,本文在准稳态模型的假设下构造三维液滴模型,综合考虑了蒸气扩散、蒸发冷却以及气相域中的自然对流这3种传输机理,对水平以及竖直基底上液滴的蒸发过程进行数值研究。通过分析气液界面上温度分布、蒸发通量分布及总蒸发率的变化,重点探究了基底过热度以及重力的改变对液滴蒸发特性的影响。结果表明：与水平基底上温度的对称分布不同,竖直基底上气液界面温度分布表现出明显的非对称性,且非对称性随基底过热度的升高而增强,最低温度点不再位于液滴顶点,而向一侧偏移。此外,水平基底上气液界面局部蒸发通量呈对称分布,各截面分布相似,而竖直基底上局部蒸发通量分布则呈现出显著的非对称性以及各截面异性,非对称性随着基底过热度的升高而增强,这是重力改变后气相域自然对流发生改变的结果。与水平基底相比,竖直基底上蒸发率更高,总蒸发时间更少。最后,基底由水平变为竖直时,液滴内部流场由对称双涡转变为非对称单涡,单涡流速显著大于双涡流速,液滴内流速随基底过热度的上升而增大,单涡环流造成了气液界面温度分布的改变以及最低温度点的偏移。     

液相沉淀反应在管式微通道反应器中的流动行为研究

以碳酸钙水相合成为模型反应,借助对流动反应过程的放大观测,从沉淀悬浮液的流变特性分析了液相沉淀反应在毫米级管式微通道中的流动行为特征以及通道堵塞的过程机理。结果表明,碳酸钙-水悬浮体系的黏度在低剪切速率下随固含率的增加而飙升,而反应通道堵塞的本质可归因于在壁面和流动主体区形成了固含率较高的局部高黏区,使流动性严重恶化。提高反应的流速加快了壁面沉积层和沉淀颗粒团聚体的形成,反而加快了堵塞;其中团聚体的形成远快于沉积层的积累,使团聚体的“架桥”虽晚于沉积层出现,却成为管路堵塞的主要因素。基于破坏流动壁面和主体的局部高黏区,设计了两种新型的微通道反应器模型,有可能为解决反应通道堵塞这一难题提供新的思路。     

二氧化钛改性α-氧化铝载体对银催化剂催化乙烯环氧化反应性能的影响

为了排除载体孔结构变化对催化性能的影响,研究了二氧化钛改性α-氧化铝载体对银催化剂催化乙烯环氧化反应性能的影响。研究结果表明,二氧化钛表面改性α-氧化铝载体对载体的比表面积、孔结构无明显影响;载体表面改性导致催化活性组分银在载体表面均匀分散,分散状况明显改善;经二氧化钛改性后载体表面与银的相互作用增强;对单负载银催化剂,由改性载体制备的银催化剂的活性和选择性均下降,改性对催化性能明显不利;对于共浸渍法制备的多组分银催化剂,低温焙烧对催化性能不利,而由经1000℃高温焙烧的二氧化钛改性载体制备的银催化剂的催化活性明显提高。研究表明,载体表面等电点降低及其与银的强相互作用是造成催化剂上金属银良好分散的主要原因;此外,银催化剂助剂的存在减弱了二氧化钛改性载体与银之间的强相互作用、抑制了环氧乙烷（EO）深度反应的活性,两者协同作用提升了多组分银催化剂的催化反应性能。     

注流孔结构对中间包流场影响的物理模拟

针对某钢厂十流中间包紊流抑制器注流孔结构不合理引起流场分布差、各流铸坯质量不均的问题,运用相似原理,使用相似比为1:3的物理模型进行水模型实验,设计不同的注流孔结构研究流体在中间包的平均停留时间曲线及流场显示特征,明晰注流孔结构对中间包流场的影响规律,优化紊流抑制器注流孔结构,达到中间包流场优化及浸入式水口各流一致性提高的目标。结果表明,长距离多流中间包在无堰坝结构条件下,紊流抑制器的注流孔内径尺寸、数量及开孔方向对中间包流场都有影响,注流孔内径的影响最为显著,数量次之。设计的最佳注流孔内径由原型的53 mm缩小至30 mm,死区比例由54.05%降至34.69%,F曲线最大标准差由0.0154降低至0.0035,中间包流场得到改善,各流一致性显著提高。当注流孔数量由1个增加至3个,死区比例由34.69%增大至46.05%,F曲线最大标准差由0.0035增大到0.0062,注流孔数目越多,流场死区比例反而越大,各水口流场的一致性越差。对长距离多流中间包,建议主要通过适当改变注流孔内径及减少孔数来改善中间包流场,提高各流一致性。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.